People are rightfully asking questions about airline security in the aftermath of the failed attempt by Nigerian jihadist and al Qaeda operative Umar Farouk Abdelmutallab to blow up Northwest Flight 253 over Detroit last month. But another question needs to be asked that is unrelated to body scanners and exploding underwear: what if, instead of a mid-air detonation, Abdelmutallab's intention had been to de-plane, enter the United States, and carry out an operation at a later time, originating within our borders? Would we have had the tools we needed to prevent this from happening?

We did not have the requisite tools when al Qaeda operatives -- including four who entered the U.S. legally and overstayed their visas -- carried out the attacks of September 11, 2001. Given this history, and the fact that Abdelmutallab himself indicated at the time of his capture that more attacks were being planned, now is clearly not the time to let our guard down on monitoring who is here from overseas and why.

Yet, that is exactly what some interest groups are asking of the Department of Homeland Security -- and the department has agreed to oblige them.

The Arab-American Anti-Discrimination Committee (ADC), along with 43 other organizations and individuals, has taken the lead in asking DHS to audit the National Security Entry-Exit Registration System (NSEERS) this month, a system designed to identify and monitor the movements of non-immigrants entering the U.S. from specific nations (and in some cases, other non-immigrants presenting a heightened security risk). But ADC has already reached its own conclusion about NSEERS, despite its use of the seemingly benign term "audit," and has called for the program to be scrapped entirely. For a variety of reasons, this call should be met with skepticism -- and the willingness of DHS to entertain proponents of such action should be met with alarm.

So what exactly did DHS agree to consider eliminating at the behest of, among others, the Council on American-Islamic Relations (CAIR), an unindicted co-conspirator in the Holy Land Foundation terrorism trial?

Developed in 2002, NSEERS essentially consists of three components. First, citizens or nationals of Iran, Iraq, Libya, Sudan and Syria are required to register with DHS at a port of entry immediately upon arrival -- this requirement also extends to individuals whom DHS inspectors identify as a potential risk to national security, irrespective of gender or nationality. Second, such individuals are required to use specially designated ports of exit when leaving the United States. Third, if anything changes with respect to such an individual's address, employment, or education while here, he is required to report such changes to DHS within ten days of the change. According to DHS, failure to comply with NSEERS could render a non-immigrant ineligible to remain in the United States and subject him or her to fines and imprisonment, unless he can show the failure was "reasonably excusable or not willful".

At one point, there was also a domestic "call-in" component to NSEERS, whereby younger males already inside the United States on non-immigrant visas from 25 countries were required to undergo further processing to verify identity, residence, and employment or matriculation. These individuals were then required to answer an immigration officer's additional questions under oath. The call-in component, designed as a one-time retroactive registration measure, was subsequently discontinued, though DHS later issued an interim rule in 2003 preserving for itself the ability to impose certain special registration requirements on non-immigrant aliens already inside the United States.

NSEERS is a necessary program. In 2003, The Government Accountability Office identified the security need for tracking non-immigrant visa overstays: "While the vast majority of overstays appear to be motivated by economic opportunities, the few who are potential terrorists could represent a significant threat to our domestic security." This "significant threat" is underscored by what a 9/11 Commission staff report had to say about the value of programs such as NSEERS:

Perhaps significantly, a senior al Qaeda detainee has stated that after the 9/11 attacks, U.S. government efforts to more closely monitor the American homeland through such actions as, as he termed it, reviewing Muslims' immigration files and deporting nonpermanent residents made al Qaeda operations more difficult. The detainee cited problems in obtaining tourist visas without interviews and instances in which visa applications were turned down even when the visa documents and passport documentation were complete. If this detainee's account is credible, these programs may have had some deterrent effect on al Qaeda planning and operations in the United States and may have required terrorists to consider other tactics for entering and remaining inside the United States or to attack elsewhere.

Despite the obvious need for NSEERS, the call to kill the program persists, as articulated in an ADC report released in March, 2009. Notably, before proceeding to trash NSEERS on dubious policy grounds, ADC concedes that the courts have repeatedly found nothing unconstitutionalabout the program. ADC is then left with a series of arguments amounting to (1) questioning the usefulness of NSEERS as a counter-terrorism tool; and (2) questioning the extent to which NSEERS reflects the "kind of America" to which we should aspire, particularly given the "morally and socially troubling" reality that "nearly every individual identified was Muslim and male."

On the question of NSEER's usefulness in counter-terrorism, the ADC report turns to analysis by former immigration officials to argue that terrorists are unlikely to volunteer themselves for scrutiny, resulting in NSEERS primarily affecting and penalizing well-meaning, otherwise law-abiding visitors. Additionally, critics of NSEERS, both inside and outside the pages of the ADC report, insist that the program risks offending the Arab/Muslim allies whose cooperation we need if we are to win against terrorism.

These assertions are unconvincing. The idea that we should dismantle NSEERS because a clever, determined jihadist will find a way around it is like saying we should get rid of the guard at the bank, since truly clever, determined bank robbers will find another way to rob the bank. NSEERS has a deterrent and disruptive effect on terrorist plots inside the United States, just as the bank guard will deter and perhaps disrupt bank robberies, though clearly not all of them and not all by himself. The fact that some terrorists will evade NSEERS is hardly a reason to eliminate the program. As the 9/11 Commission staff report asserted: "…the proposition that these programs had the potential to disrupt and perhaps to deter terrorist plots forming inside the United States after 9/11 certainly has some support."

With respect to the possible effects of NSEERS on relationships with countries whose help we need, nations claiming to be American allies should be open to reevaluating their misgivings in recognition of the bigger picture. They should recognize, with prodding from us as necessary, that registration of their visiting citizens is a small price to pay not only for preventing terrorism inside the U.S., but also for enabling us to avoid an alternative that many would argue is perfectly legal and reasonable: an outright ban on all visitors to the U.S. from countries where jihadist governments and movements are prevalent -- a move not hard to imagine or justify during a time of war.

Which brings us to how this all bears on "what kind of America" we should be. We are a nation of laws, and we are a nation historically welcoming visitors seeking to work and study here. We should continue to be both. But as we fight a war put upon us by those who carry out violent jihad, we must also be a nation of common sense and candidly identify those locations from which jihad emanates, and use that knowledge to protect all law-abiding individuals inside the United States -- citizens, residents and visitors alike.

To be sure, there are elements of NSEERS that need improvement. Currently, countries that come within automatic scrutiny at ports of entry are limited to a select handful. In light of what we know about the location of jihad, that automatic scrutiny should extend to individuals who are from or have previously visited those same countries to which "call-in" registration previously applied -- Afghanistan, Pakistan, Saudi Arabia, Yemen, and several others.

As with any federal program, NSEERS should also be evaluated with an eye towards increasing efficiencies, reducing costs, and avoiding the bureaucratic inertia typical of so many federal programs. But while it is reasonable to question, as the ADC report does, the effectiveness of providing notice of NSEERS requirements through the byzantine Federal Register, the report leaves out that the DHS website publishes not only the NSEERS basics, but had also published the numerous "call-in" notices -- in English, Arabic, Urdu, Farsi, Pashto, and other languages.

Clearly, given the phenomenon of "homegrown jihad" both here and in Europe, the geographic location of jihadist movements is not the entire story. But the notion that such considerations should not be part of the calculation defies reason and ignores reality. Ironically, we can find a potent illustration on this score by President Obama and the Transportation Security Administration.

President Obama recently decided to require individuals traveling to the U.S. from terrorism-sponsoring countries along with "other countries of interest" including Afghanistan, Algeria, Iraq, Lebanon, Libya, Nigeria, Pakistan, Saudi Arabia, Somalia and Yemen, to undergo enhanced screening before boarding the plane overseas. The President, in making this decision, appropriately prioritized the security of airline passengers over the potential hurt feelings of these nations. The idea that we should apply extra scrutiny to passengers from these countries before they board the aircraft, but then decline to apply such scrutiny to those same passengers upon their arrival for extended stays in the U.S., is simply unsound policy -- one that will only succeed in changing the location of the terrorist act from our airliners to our streets.

Now is not the time to let our guard down when it comes to homeland security. As President Obama claims to be determined to fix "systemic failure" on this front that almost cost many American lives, he must not weaken that system by scrapping the constitutional and worthwhile NSEERS program.

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